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Carbon and nitrogen isotopic compositions of alkyl porphyrins from the Triassic Serpiano oil shaleThe carbon and nitrogen isotopic compositions of seven of the most abundant alkylporphyrins from the Serpiano oil shale (marine, Triassic) were determined. For the C31 and C32 butanoporphyrins, values of delta 13CPDB and delta 15NAIR averaged -24.0% and -3.1%. In contrast, the C31 and C32 methylpropanoporphyrins, DPEP, and a C30 13-nor etioporphyrin had delta 13C and delta 15N values averaging -27.5 and -3.3%, respectively. Carbon and nitrogen isotopic values for kerogen averaged -30.8 and -0.9, whereas those for total extract averaged -31.6, and -4.0%. The butanoporphyrins apparently derive from a biological source different from that giving rise to the other porphyrins, their 13C enrichment not being related to carbon isotopic fractionation accompanying diagenetic reactions. The delta 15N values for all the porphyrins indicate that the depletion of 15N observed in the kerogen is of primary origin. Consistent with the very high abundance of hopanoids and methyl hopanoids in the aliphatic hydrocarbon fraction, it is suggested that cyanobacterial fixation of N2 may have been the main cause of 15N depletion.
Document ID
20040090302
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Chicarelli, M. I.
(School of Chemistry, University of Bristol United Kingdom)
Hayes, J. M.
Popp, B. N.
Eckardt, C. B.
Maxwell, J. R.
Date Acquired
August 21, 2013
Publication Date
January 1, 1993
Publication Information
Publication: Geochimica et cosmochimica acta
Volume: 57
Issue: 6
ISSN: 0016-7037
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: NAGW-1940
CONTRACT_GRANT: 20107-AC2
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Exobiology
NASA Discipline Number 52-30
NASA Program Exobiology
Non-NASA Center

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